Patent GB-714894-A (GB)
Title: Improvements in and relating to apparatus for bending tubular lamps
IPC: C03B23/06
Filed: 1952-08-11
Abstract: 714,894. Making tubular electric lamps. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 11, 1952 [Aug. 14, 1952], No. 20158/52. Class 39 (2) Apparatus for heating and bending a tubular electric lamp comprises a head for supporting the lamp upon a carrier that advances it through a plurality of work stations while being heated to a plastic condition by heating means which travels with it to the bending station where it is bent to the required configuration. The heating means, which preferably comprises an oven, is arranged to be locked to the workcarrying head during an indexing movement from an initial position to the bending-station, and subsequently returned to its initial position along the path of travel of the head. The lamp is suspended vertically from the carrier, and the extent of the heating is controlled by means which engages the lower end of the lamp and is displaced downwardly when the lamp is heated sufficiently to stretch due to its own weight. In the example the heating and controlling mechanisms are mounted on the frame 1 of the machine at two adjacent work stations. A and B, the mechanism shown being a modification of the heating and bending means occupying two stations of the machine described in Specification 673,104. A single tubular lamp 2 is suspended from each of a succession of heads 3 around the periphery of a turret 4 and after being preheated in an oven is indexed to station A where it is positioned by jaws 17, 18 closing upon its lower end, the jaws being mounted at the upper ends of vertical shafts 14, 15 carried by a bracket 16 and moved in opposite directions by pinions at their upper ends and a link 26 and crank 25 at their lower end. The crank 25 is pivoted eccentrically on a pinion 23 driven by a motor 21 controlled by a switch with an actuating arm that is operated by a vertical control pin 9, Fig. 4, when the latter returns from station B to station A, the closing of the jaws being completed by half a revolution of pinion 23. A vertical positioning pin 9 is next lifted and seats against the lower end of the lamp whereupon the jaws 17, 18 are opened by a further half revolution of pinion 23 and their actuating motor 21 is stopped by a cam 28 opening the switch 30. The upward movement of the pin 9 is effected by the closure of a switch 33 by a cam 32 on the pinion shaft 29 which operates a solenoid valve and lifts a ram 37 projecting upwardly from an hydraulic cylinder 38, located directly under the bottom end of the pin 9. By the upward movement of the pin 9 an arm 34, Fig. 4, linked thereto and carrying a pair of rollers 42 on its opposite sides causes the tilting of a latch 44 which is pivoted at 47 and has an intermediate projection 43 and a projection or stop 45, the rollers 42 being moved from below the projection 43 to a position above it so that the pin 9 is prevented from dropping downwardly and the counterweight 50 on arm 34 causes the upper end of the pin to exert upward pressure against the lower end of the lamp. Tilting of the lever 34 also closes a switch 51 mounted above it and starts a motor 54, Fig. 2, mounted on a bracket 54 on a saddle 19 which provides a guide and support for a slidable carriage 56 for the oven 10, the motor being connected through a speed reducer to links 67, 68 which move the oven radially outwardly from an inner central position into heating relation to the lamp 2 at station A. The two halves 10<SP>1</SP>, 10<SP>11</SP> of the oven are secured upon vertical shafts 55, 55<SP>1</SP> each provided at its lower end with an arm 62 carrying a roller which engages within a longitudinal cam slot 71 or 71<SP>1</SP> in the base of the saddle 19, the cam slots being so shaped that movement of the carriage 56 and oven 10 towards the lamp effects the opening of the two halves 10, 101 of the oven during the first part of the movement and their closure upon the lamp during the latter part, the carriage driving motor 53 being stopped immediately by a cam 72 on the speed reducer shaft engaging the operating arm of switch 73. Heating of the tube by the oven commences during the dwell at station A and continues during the indexing to station B, the latter movement being effected through a spider 79 (shown in part in Fig. 2), which is secured on the axial shaft of the turret and is provided on its underside, near the edge, with a series of spaced rollers mounted on vertical pins and engaged in turn by the edge of a cam on the main horizontal shaft of the machine. Alternate rollercarrying pins are extended upwardly through the spider 79 and carry rollers 82 arranged to be engaged by the forked end of a slide 81 mounted in a block 85 on the underside of a bracket 86 which is secured to a vertical bar 87 extending down from one side of the saddle. A locking engagement of the slide 81 and a roller 82 is effected by a cam 83, Fig. 3 (not shown), on the main shaft 75 closing a switch to operate the valve 93 of a compressed air supply to a cylinder 91, whereby the slide 81 is moved to its operative position. The saddle 19, which is mounted on rollers on a pair of arcuate rails 88, 89 is thus coupled to the turret indexing system so that the oven moves with the lamp from station A to station B and the lamp tube is heated to a plastic condition and elongates so that it pushes the control pin 9 downwardly, thereby causing the oven to open and retract from the lamp 2 and also causing the tube bending means to operate as described in Specification 673,104. The oven is subsequently moved back to its inner position, the control pin 9 is retracted and, with the oven, is returned to station A for a succeeding cycle of operations.